It IS possible, relatively infrequently, to get food poisoning from eating reheated rice - the responsible " bug " is Bacillus cereus, the spores of which can survive cooking, and may form multiplying bacteria if the rice is left standing at room temperature. A few hours later these may cause vomiting/diarrhoea which lasts about a day. Ideally rice should be served once it’s been cooked ; or cooled quickly ( within an hour ), and refrigerated for no more than a day before thoroughly and uniformly reheating ( once ).


Microwaves should kill most bacteria - it’s thought to be the heating ( of water present in food ) - rather than the electromagnetic radiation directly - which needs to be thorough and uniform ( not uneven ).


There are of course many causes of diarrhoea / vomiting related to food / water, including those where NO " bug " is responsible - such as spicy foods, change of diet with travelling, and drugs like antibiotics.


Most are gut infections caused by many different " micro-organisms ". These may be bacteria such as Campylobacter, Cholera, Clostridia, E.coli, Listeria, Salmonella, Shigella, Staph. aureus, and Typhoid ; viruses such as Hepatitis A, Rotavirus, and Norovirus ; and others such as Amoeba.


Food poisoning is very common, most cases being mild and therefore unreported to doctors, so we don’t know the true frequency. For example, there are about 60,000 confirmed cases of food poisoning each year in the UK, but it’s estimated the real number is 10 times greater. Similarly we don’t know the true numbers in the Philippines.


As for " natural immunity " ( " resistance " ) from acquired infections, that may well contribute to the surprisingly low apparent numbers of cases of food poisoning, considering unhygienic practices in storage ( perhaps with no 'fridge ) and preparation of food ; and impure water consumption. Natural immunity is good, but is neither complete, nor an excuse to take no care ! If vaccines are available, they may be considered for prevention of more serious infections such as Cholera ; Hepatitis A ; Typhoid ; and Rotavirus in children.


Many links provide more details - see for example :-


# 8 here :- http://filipinaroses.com/showthread....to-Philippines


http://www.traveldoctor.co.uk/diarrhoea.htm